BUG: Correct ExcelWriter (#472)

closes #462

Author: bashtage

pandas-stubs/io/excel/_base.pyi

@@ -104,7 +104,7 @@ class ExcelWriter:
     def __init__(
         self,
         path: FilePath | WriteExcelBuffer | ExcelWriter,
-        engine: Literal["auto", "openpyxl", "pyxlsb", "odf"] | None = ...,
+        engine: Literal["auto", "openpyxl", "odf", "xlsxwriter"] | None = ...,
         date_format: str | None = ...,
         datetime_format: str | None = ...,
         mode: Literal["w", "a"] = ...,
@@ -115,11 +115,11 @@ class ExcelWriter:
     @property
     def supported_extensions(self) -> tuple[str, ...]: ...
     @property
-    def engine(self) -> Literal["openpyxl", "pyxlsb", "odf"]: ...
+    def engine(self) -> Literal["openpyxl", "odf", "xlsxwriter"]: ...
     @property
     def sheets(self) -> dict[str, Any]: ...
     @property
-    def book(self) -> Workbook | OpenDocument | pyxlsb.workbook.Workbook: ...
+    def book(self) -> Workbook | OpenDocument: ...
     @property
     def date_format(self) -> str: ...
     @property

pyproject.toml

@@ -52,7 +52,8 @@ tables = { version = ">=3.7.0", python = "<3.11" }
 lxml = { version = ">=4.7.1,<4.9.0", python = "<3.11" }
 pyreadstat = ">=1.2.0"
 xlrd = ">=2.0.1"
-pyxlsb = ">=1.0.9"
+xlsxwriter = ">=3.0.3"
+pyxlsb = ">=1.0.10"
 odfpy = ">=1.4.1"
 xarray = ">=22.6.0"
 tabulate = ">=0.8.10"

tests/test_io.py

@@ -11,6 +11,7 @@
     Dict,
     Generator,
     List,
+    Literal,
     Union,
 )
 
@@ -694,12 +695,46 @@ def test_excel_writer():
         check(assert_type(ef.close(), None), type(None))
 
 
+def test_excel_writer_engine():
+    with ensure_clean(".xlsx") as path:
+        with pd.ExcelWriter(path, engine="auto") as ew:
+            check(assert_type(ew, pd.ExcelWriter), pd.ExcelWriter)
+            DF.to_excel(ew, sheet_name="A")
+
+    with ensure_clean(".xlsx") as path:
+        with pd.ExcelWriter(path, engine="openpyxl") as ew:
+            check(assert_type(ew, pd.ExcelWriter), pd.ExcelWriter)
+            DF.to_excel(ew, sheet_name="A")
+            check(
+                assert_type(ew.engine, Literal["openpyxl", "odf", "xlsxwriter"]),
+                str,
+            )
+
+    with ensure_clean(".ods") as path:
+        with pd.ExcelWriter(path, engine="odf") as ew:
+            check(assert_type(ew, pd.ExcelWriter), pd.ExcelWriter)
+            DF.to_excel(ew, sheet_name="A")
+            check(
+                assert_type(ew.engine, Literal["openpyxl", "odf", "xlsxwriter"]),
+                str,
+            )
+
+    with ensure_clean(".xlsx") as path:
+        with pd.ExcelWriter(path, engine="xlsxwriter") as ew:
+            check(assert_type(ew, pd.ExcelWriter), pd.ExcelWriter)
+            DF.to_excel(ew, sheet_name="A")
+            check(
+                assert_type(ew.engine, Literal["openpyxl", "odf", "xlsxwriter"]),
+                str,
+            )
+
+
 def test_excel_writer_append_mode():
     with ensure_clean(".xlsx") as path:
         with pd.ExcelWriter(path, mode="w") as ew:
             DF.to_excel(ew, sheet_name="A")
-        with pd.ExcelWriter(path, mode="a") as ew:
-            pass
+        with pd.ExcelWriter(path, mode="a", engine="openpyxl") as ew:
+            DF.to_excel(ew, sheet_name="B")
 
 
 def test_to_string():